San Francisco Mayor Gavin Newsom formally announces his candidacy for California governor at Facebook headquarters in Palo Alto, Calif., Tuesday, April 21, 2009. Entering a race that could see him competing against men 15 and 30 years his senior, the 41-year-old Democrat pointedly used YouTube and the social networking sites Twitter and Facebook to disclose that he would seek his party's nomination to succeed Gov. Arnold Schwarzenegger. (AP Photo/Paul Sakuma)

Photo: Paul Sakuma, AP

San Francisco Mayor Gavin Newsom formally announces his candidacy...

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(left to right) Elliott Schrage, Facebook's, vice president of communications and public policy, Jennifer Siebel, mayor Newsom's wife, San Francisco Mayor Gavin Newsom and Chris Kelly, Facebook's, chief privacy officer,head of public policy, tour the company headquarters of Facebook, on Tuesday April 21, 2009 in Palo Alto, Calif., as Newsom officially announced his run for governor of California, on the internet using YouTube, Twitter and Facebook.

Photo: Michael Macor, The Chronicle

(left to right) Elliott Schrage, Facebook's, vice president of...

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Gavin Newsom meets with the media during a visit to the internet company Facebook on Tuesday April 21, 2009 in Palo Alto, Calif., as the San Francisco Mayor officially announced his run for governor of California, on the internet using YouTube, Twitter and Facebook.

San Francisco Mayor Gavin Newsom formally declared his 2010 campaign for California governor Tuesday with a tech-savvy approach - simultaneous announcements on Facebook, Twitter and YouTube - and a message of "generational" change aimed at the influential young "millennial" voters who helped elect President Obama.

Newsom, in an interview with The Chronicle, said his announcement dramatizes his intention to offer voters a far different vision, and resume, than other potential candidates. The mayor said his campaign represents "an opportunity to - I want to use the phrase 'turn the page' - but it is an opportunity to spin to the future. That's something you'll hear me promoting a lot in the next year and a half."

Clearly aiming to draw a contrast with two-term former governor and current state Attorney General Jerry Brown, 71, considered a likely front-runner in the race, Newsom, 41, quoted Bobby Kennedy: "The world needs the qualities of youth - not a time of life, but a state of mind, a quality of imagination."

"I should give that quote to Jerry," he said with a smile.

Newsom, in the three-minute YouTube announcement that unveiled his formal bid, said the state is sorely in need of fresh blood - and fresh ideas - to tackle its myriad economic and social problems.

"We can't afford to keep returning to the same old tired ideas and expect a different result," he said.

Newsom argued that his record on issues like the environment and green technology, health care and government spending "isn't conservative or progressive. It's just plain smart for everyone."

With about 14 months to go before the 2010 gubernatorial primaries, Newsom's formal announcement follows an exploratory campaign that began in July, when he began traveling the state meeting voters and raising money.

Political observers said that while the use of social networks in politics has become more common, the San Francisco mayor's unusually ambitious debut represented a political campaign landmark.

Reaching an estimated half-million Newsom supporters within hours - and raising some $15,000 in donations - Tuesday's effort used Facebook, where Newsom has 40,000 followers, as well as Twitter, where there are 270,000 Newsom subscribers, in addition to YouTube and his Web site, GavinNewsom.com.

"The way that Gavin Newsom announced will become standard practice in the post-Obama era of politics," said Simon Rosenberg, who heads NDN, which studies Democratic policy issues. "We're seeing a reinventing of politics ... and in a state as wired as California, and a campaign as expensive as this one will be, the candidates who can figure out how to tap into the power and passion of their supporters will have an advantage."

Newsom, in his interview with The Chronicle, suggested that his "generational" outlook toward technology, as well as his entrepreneurial business experience and resume, draw clear distinctions between himself and other candidates who may crowd the 2010 gubernatorial contest.

On the Democratic side, they include Brown, who has also been California secretary of state, mayor of Oakland and a three-time presidential candidate; as well as Los Angeles Mayor Antonio Villaraigosa, a former state Assembly speaker; and Lt. Gov. John Garamendi, a former state insurance commissioner and legislator.

Among Republicans, state Insurance Commissioner Steve Poizner and former eBay CEO Meg Whitman - two wealthy Silicon Valley-based technology executives - are still raising money through exploratory committees, as is former Rep. Tom Campbell, also from Silicon Valley.

"My experience is very different" from other Democrats, Newsom told The Chronicle. "I come from the private sector. ... I created real jobs, started businesses, wrote business plans, went out and got investors, took entrepreneurial risks, organized around those ideas and grew a business of over 1,000 employees."

The mayor, now in his second term as chief executive of both the city and county of San Francisco - one of the state's most liberal bastions - said he is eager to contrast his city's record with the record of Brown in Oakland and Villaraigosa in Los Angeles.

"Let's talk about what we did on health care. ... Let's talk about substantively, what we did on education," he said. "Let's talk about the environment. ... Let's talk about anti-poverty strategies ... and reform strategies and economic development strategies."

The candidate's announcement video, which premiered on his Web page and on YouTube, utilized three languages - English, Spanish and Mandarin - as well as images of solar technology, schools and health care facilities.

It argued that Newsom has created jobs, helped San Francisco establish a rainy day reserve and "sound fiscal" budgetary policy, and has tackled the challenge of providing universal health care to the uninsured.